Today's podcast - released on none other than International Podcast Day...yes, it's a thing...is a follow up interview with Evan Jordan of Oklahoma State University.

If you are a new listener to the Laughter Research Podcast, you might like to check out the previous interview HERE. Evan has been the lead investigator on a study which has been examining various aspects of infant development. Needless to say, of particular interest to me is the laughter aspect of the research.

Evan sought to uncover the extent of contagiousness of positive emotions in infants, with a particular focus upon laughter. You might be very surprised by the findings, but you'll have to listen in to find out more on that.

We discuss the challenges and joys of working with infants in research and we discuss the future directions for research in the arena of contagious laughter. We also ponder the possibility of Evan earning an Oscar for her thank you 'Shout Out' at the end of the podcast.

During the conversation I mention an excellent book by Robert Provine. Check it out on Amazon. It's well worth picking up.

We also mention the innate aspect of laughter and discuss how infants who are born deaf and blind will develop laughter around the same stage of development as typical children.

A couple of interesting papers related to this topic:

No. 1 relates to the acoustic profile of laughter in congenitally deaf people:

In this paper the authors attribute some acoustic variation between the laughter of hearing people and deaf people as being "Due to a combination of the physiological and social factors that routinely affect profoundly deaf individuals, including low overall rates of vocal fold use and pressure from the hearing world to suppress spontaneous vocalizations." - In other words, invisible social rules influence how and when people laugh.

"Deaf individuals report experiencing social pressure to suppress spontaneous vocalizations, as these can be uncomfortably loud for the hearing (Leder and Spitzer, 1993)."

This paper is particularly relevant as it shows us how laughter is fluidly incorporated into more complex cognitive interactions and it indicates that the appropriate timing of 'conversational' laughter is a learned skill.